Communication systems of recent railroad cars are being configured in a wireless manner rather than a wired manner or switched to a wireless manner, and there is ongoing research for implementing autonomous driving using information transmitted and received through wireless communication.
The wireless communication manner has features that make it highly convenient, but has a drawback in that safety and security are significantly low.
For example, a railroad car in which a wireless vehicular communication device is installed is exposed to intentional or unintentional jamming signals while travelling. In some situations, the vehicular communication device may break down due to the jamming signals, and safe travel of the railroad cars may be threatened thereafter in a remaining travel distance.